The present invention relates, in general, to a casing arrangement for a turbocharger of an internal combustion engine.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
German Pat. No. DE 100 22 052 C2 discloses a turbine casing having an inlet funnel, a rotor casing, which is surrounded by an outer housing and made two-part configuration, and an exhaust pipe. The rotor casing is welded to one end of the exhaust pipe. The other end of the exhaust pipe is welded to the outer housing in an area of a connection flange. Welding of the exhaust pipe with the rotor casing as well as with the connection flange results in significant thermal stress of the internal system comprised of the rotor casing and the exhaust pipe. This thermal stress is compounded by the provision of an insulating air gap between the rotor casing and the outer housing to shield the outer housing from the rotor casing and the flow passage. While a direct contact of the outer housing with exhaust is hereby avoided, the downside is, however, that the outer housing is significantly cooler. When high operating temperatures are involved, this thermal stress causes premature material fatigue and thus premature breakdown of the rotor casing and/or exhaust pipe. In addition, deformation caused by heat may result in a contact between the rotor casing and the rotor, leading to a sudden breakdown of the turbocharger.
It would therefore be desirable and advantageous to provide an improved casing arrangement for a turbocharger of an internal combustion engine to obviate prior art shortcomings and to minimize a passage of exhaust about the rotor.